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Text-only version of these pages for regular e-updates and ticket booking |
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  Click an image to see larger view Facts and figures A rare and visionary gesture Plant tower Artworks Auditorium Organ Exterior Interiors |
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| Construction Unusually, The Bridgewater Hall is neither concrete- nor steel-framed, but is mostly formed from solid, reinforced concrete, moulded and cast like some vast sculpture. This gives it enormous density and mass - an acoustic ideal - and for more than a year the contractor's main activity was shuttering, reinforcing and pouring more than 2,500 loads of concrete. Above the auditorium is a most remarkable roof, an engineering triumph which is, literally, the crowning glory of the building. It has three separate layers, the most substantial being the middle one; the massive ceiling of concrete-covered steelwork which spans the concert hall between pairs of tall, slim columns. Its intricate shape is a vital ingredient in the acoustic perfection of the space and every concrete slab is subtly twisted to diffuse sound effectively in the upper parts of the hall. Too wide and substantial to be self-supporting, it is held in place by the bottom layer; a tensioning system of struts and tie-rods hanging into the auditorium like some inverted suspension bridge. Despite its visual impact, this inner steelwork is acoustically 'invisible' and has no influence on the quality of the sound. Above the concrete ceiling, a huge acoustic void houses technical systems and winches for lowering the chandeliers. Higher still is the third, outer layer; a light steel framework supporting acoustic panels covered externally with thin sheets of reflective, highgrade stainless steel - relatively new as a roofing material, but lighter and infinitely more durable than lead, its traditional equivalent. The soffits are gently illuminated at night, creating the illusion that the roof hovers, magically weightless, above the building. To ensure that the Hall's carefully designed acoustic remains cocooned from all outside noise and vibration, the entire structure floats free of the ground on almost three hundred, earthquake proof isolation bearings. These sets of mighty steel springs ensure that there is no rigid connection between the 22,500 ton building and its foundations. In the Hall's undercroft, a forest of foundation columns, each capped with a cluster of spring units, create a mysterious silent world as compelling and dramatic as any of The Bridgewater Hall's more public spaces. |
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